老师为什么背影导航动画实现不出来，代码也没错啊。

.st-scrool{

left:0;

top:0;

-webkit-transform:translate3d(0,0,0);

-moz-transform:translate3d(0,0,0);

-o-transform:translate3d(0,0,0);

-ms-transform:translate3d(0,0,0);

transform:translate3d(0,0,0);

-webkit-backface-visibility:hidden; 

    -webkit-transition:all 0.6s ease-in-out;

-moz-transition:all 0.6s ease-in-out;

-o-transition:all 0.6s ease-in-out;

-ms-transition:all 0.6s ease-in-out;

transition:all 0.6s ease-in-out;

}